A great variety of mobile phone products are widely used in real life, and each type of mobile phone has a different charging jack location and earphone jack location. At a dark night or in a dim place, when a user needs to insert a mobile phone charger or an earphone, it is difficult for the user to find a jack location correctly at the first time. This brings unnecessary troubles to the user. Moreover, due to physical characteristics of a universal serial bus (USB) jack, a mobile phone has a fixed jack location for USB insertion, but the user often improperly inserts the USB jack into the mobile phone in an opposite direction in a use process. This case also brings unnecessary troubles to the user in the use process.